The present invention relates to a parallel data processor in which a plurality of data processor elements such as microprocessors are organically coupled with each other to achieve parallel data processing and to a microprocessor applicable thereto, for example, to a technology effectively applied to a computer operating at an ultra high speed.
As a method of increasing the processing speed of computers, a technology in which a large number of computer (data processor) elements are arranged to execute parallel operations has developed. In this situation, the processing performance of the overall computer system is determined by the data transfer speed between the computer elements thus arranged in a parallel fashion. For this purpose, a technology of increasing the speed and efficiency of data transfer between plural computer elements disposed in parallel has been described in the U.S. Ser. No. 07/369,252, filed on Jun. 20, 1989 and assigned to the present assignee (JP-A-1-320564) now abandoned. The parallel processor disclosed therein includes a central processing unit (CPU) and microprocessors, each including a local memory, a plurality of ports for establishing connection between the microprocessors, and a path for transferring data selectively from one of the ports to other ports, thereby enabling re-configuration of connections between the respective microprocessors according to a processing method so as to achieve various kinds of processing through parallel operations.
The present inventors have investigated methods of data transfer between a large number of computer elements in more detail and have recognized the following facts. Even when the prior art above is adopted in a parallel computer, for the configuration of connections between the computer elements, there is employed a two-dimensional grid (matrix) connection, a tree connection, or the like. In either case, to a selected one of the computer elements, only two to four computer elements adjacent thereto can be directly connected. In an ultra parallel computer system of a large size in which about 10.times.10 to about 30.times.30 computer elements are arranged, for a transfer of data from a computer element to another computer element, it is required to transfer the data via ten to thirty other computer elements. This means that the processing speed and efficiency are limited when processing a great volume of data in the system.